U.S. patent application number 11/700830 was filed with the patent office on 2007-08-02 for toothed power transmission belt with cloth component thereon.
This patent application is currently assigned to Mitsuboshi Belting Ltd.. Invention is credited to Yasuyuki Izu, Masakuni Yoshida.
Application Number | 20070178792 11/700830 |
Document ID | / |
Family ID | 37998350 |
Filed Date | 2007-08-02 |
United States Patent
Application |
20070178792 |
Kind Code |
A1 |
Yoshida; Masakuni ; et
al. |
August 2, 2007 |
Toothed power transmission belt with cloth component thereon
Abstract
A power transmission belt having a body with a length, an
inside, and an outside. The body has a plurality of teeth formed on
the inside of the body and spaced along the length of the body. The
body has a first surface at the inside of the body defined at least
in part by the teeth. A cloth component has a first side attached
to the first surface and a second side exposed to engage a
cooperating pulley. The cloth component has first fibers at the
first side of the cloth component with a first performance
characteristic and second fibers at the second side of the cloth
component with a second performance characteristic. The first side
of the cloth component has different properties than the second
side of the cloth component by reason of the presence of the first
and second fibers.
Inventors: |
Yoshida; Masakuni; (Kobe,
JP) ; Izu; Yasuyuki; (Kakogawa, JP) |
Correspondence
Address: |
WOOD, PHILLIPS, KATZ, CLARK & MORTIMER
500 W. MADISON STREET
SUITE 3800
CHICAGO
IL
60661
US
|
Assignee: |
Mitsuboshi Belting Ltd.
|
Family ID: |
37998350 |
Appl. No.: |
11/700830 |
Filed: |
January 31, 2007 |
Current U.S.
Class: |
442/293 ;
442/203 |
Current CPC
Class: |
Y10T 428/24603 20150115;
Y10T 442/3911 20150401; Y10T 442/3179 20150401; F16G 1/28 20130101;
Y10T 428/2457 20150115; Y10T 428/24612 20150115 |
Class at
Publication: |
442/293 ;
442/203 |
International
Class: |
D03D 13/00 20060101
D03D013/00; B32B 25/10 20060101 B32B025/10 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 31, 2006 |
JP |
21619/2006 |
Oct 3, 2006 |
JP |
271458 |
Claims
1. A power transmission belt comprising: a body with a length, an
inside, an outside, and laterally spaced and oppositely facing side
surfaces, the body having a plurality of teeth formed on one of the
inside and outside of the body and spaced along the length of the
body, the body having a first surface at the one of the inside and
outside of the body defined at least in part by the teeth; and a
cloth component having oppositely facing first and second sides
with the first side attached to the first surface and the second
side exposed to engage a pulley cooperating with the power
transmission belt, the cloth component comprising first fibers at
the first side of the cloth component with a first performance
characteristic and second fibers at the second side of the cloth
component with a second performance characteristic that is
different than the first performance characteristic, the first side
of the cloth component having different properties than the second
side of the cloth component by reason of a presence of the first
and second fibers.
2. The power transmission belt according to claim 1 wherein the
body comprises rubber that defines at least a part of the first
surface and at least one load carrying member is embedded in the
rubber and extends lengthwise of the body adjacent the other of the
inside and outside of the body.
3. The power transmission belt according to claim 1 wherein the
body comprises rubber that defines at least a part of the first
surface, the first fibers comprise a composition that adheres
strongly to the rubber at the first surface and the second fibers
comprise a composition with a low coefficient of friction.
4. The power transmission belt according to claim 3 wherein the
first fibers have a composition that adheres more strongly to the
rubber than the composition of the second fibers and the second
fibers have a composition with a lower coefficient of friction than
a coefficient of friction of the first fibers.
5. The power transmission belt according to claim 3 wherein the
second fibers have good abrasion resistance characteristics.
6. The power transmission belt according to claim 1 wherein the
cloth component comprises a double cloth construction.
7. The power transmission belt according to claim 3 wherein the
second fibers comprise fluorine fibers.
8. The power transmission belt according to claim 3 wherein the
cloth component comprises warp yarns comprising nylon fibers and
weft yarns comprising fluorine fibers, nylon fibers, and
polyurethane elastic yarns.
9. The power transmission belt according to claim 8 wherein the
cloth component comprises a double cloth construction, the first
fibers have a composition that adheres more strongly to the rubber
than a composition of the second fibers and the second fibers have
a composition with a lower coefficient of friction than a
coefficient of friction of the first fibers.
10. The power transmission belt according to claim 7 wherein the
second fibers have a coefficient of friction less than a
coefficient of friction for the first fibers.
11. The power transmission belt according to claim 10 wherein the
cloth component comprises warp yarns comprising fluorine fibers,
nylon fibers, and polyurethane elastic yarns and weft yarns
comprising nylon fibers.
12. The power transmission belt according to claim 11 wherein the
cloth component comprises a double cloth construction.
13. The power transmission belt according to claim 12 wherein the
first fibers have a composition that adheres more strongly to the
rubber composition than a composition of the second fibers.
14. The power transmission belt according to claim 13 wherein the
weft yarns comprise a plurality of first weft yarns at the first
side of the cloth component and a plurality of second weft yarns at
the second side of the cloth component and at least the plurality
of second weft yarns comprises fluorine fibers.
15. The power transmission belt according to claim 13 wherein the
warp yarns comprise a plurality of first warp yarns at the first
side of the cloth component and a plurality of second warp yarns at
the second side of the cloth component and at least the second warp
yarns comprise fluorine fibers.
16. The power transmission belt according to claim 14 wherein from
20-100% of the warp yarns are woven by being intertwined with the
second weft yarns.
17. The power transmission belt according to claim 15 wherein from
20-100% of the weft yarns are woven to by being intertwined with
the second warp yarns.
18. The power transmission belt according to claim 16 wherein the
second weft yarns comprise urethane elastic yarns that have core
parts with exposed circumferences and fluorine fibers are applied
on the exposed circumferences of the core parts.
19. The power transmission belt according to claim 17 wherein the
second warp yarns comprise urethane elastic yarns that have core
parts with exposed circumferences and fluorine fibers are applied
on the exposed circumferences of the core parts.
20. The power transmission belt according to claim 16 wherein the
first weft yarns comprise urethane elastic yarns that have core
parts with exposed circumferences and nylon fibers are applied on
the exposed circumferences of the core parts.
21. The power transmission belt according to claim 17 wherein the
first warp yarns comprise urethane elastic yarns that have core
parts with exposed circumferences and nylon fibers are applied on
the circumferences of the core parts.
22. The power transmission belt according to claim 12 wherein the
second side of the cloth component has an area and the fluorine
fibers in the cloth component are exposed on the second side over
from 30-100% of the area of the second side.
23. The power transmission belt according to claim 3 wherein the
second fibers comprise fluorine fibers having a coefficient of
friction less than a coefficient of friction for the first fibers,
and the first side of the cloth component comprises five sateen
weaves comprising fibers that adhere more strongly to the rubber
than fibers on the second side of the cloth component, wherein the
cloth component comprises warp yarns comprising nylon fibers and
weft yarns comprising fluorine fibers, nylon fibers, and
polyurethane elastic yarns.
24. The power transmission belt according to claim 8 wherein the
fluorine fibers comprise at least one of a polytetrafluoroethylene,
a polytrifluoroethylene, a tetrafluoroethylene-hexafluoropropylene
copolymer, a tetrafluoroethylene-perfluoroalkoxyethylene copolymer,
and a tetrafluoroethylene-ethylene copolymer.
25. The power transmission belt according to claim 11 wherein the
fluorine fibers comprise at least one of a polytetrafluoroethylene,
a polytrifluoroethylene, a tetrafluoroethylene-hexafluoropropylene
copolymer, a tetrafluoroethylene-perfluoroalkoxyethylene copolymer,
and a tetrafluoroethylene-ethylene copolymer.
26. The power transmission belt according to claim 23 wherein the
fluorine fibers comprise at least one of a polytetrafluoroethylene,
a polytrifluoroethylene, a tetrafluoroethylene-hexafluoropropylene
copolymer, a tetrafluoroethylene-perfluoroalkoxyethylene copolymer,
and a tetrafluoroethylene-ethylene copolymer.
27. The power transmission belt according to claim 8 wherein the
fluorine fibers comprise polytetrafluoroethylene fibers and a
polytetrafluoroethylene content in the polytetrafluoroethylene
fibers is from 90-100 parts by mass per 100 parts by mass of the
polytetrafluoroethylene fiber.
28. The power transmission belt according to claim 11 wherein the
fluorine fibers comprise polytetrafluoroethylene fibers and a
polytetrafluoroethylene content in the polytetrafluoroethylene
fibers is from 90-100 parts by mass per 100 parts by mass of the
polytetrafluoroethylene fiber.
29. The power transmission belt according to claim 23 wherein the
fluorine fibers comprise polytetrafluoroethylene fibers and a
polytetrafluoroethylene content in the polytetrafluoroethylene
fibers is from 90-100 parts by mass per 100 parts by mass of the
polytetrafluoroethylene fiber.
30. The power transmission belt according to claim 23 wherein the
second side of the cloth layer has an area and the fluorine fibers
on the cloth layer are exposed on the second side over from 50-100%
of the area of the second side of the cloth layer.
31. The power transmission belt according to claim 24 wherein the
second side of the cloth layer has an area and the fluorine fibers
on the cloth layer are exposed on the second side over from 50-100%
of the area of the second side of the cloth layer.
32. The power transmission belt according to claim 27 wherein the
second side of the cloth layer has an area and the fluorine fibers
on the cloth layer are exposed on the second side over from 50-100%
of the area of the second side of the cloth layer.
33. The power transmission belt according to claim 1 wherein a
resorcin-formalin-latex treatment is applied to the cloth
component.
34. The power transmission belt according to claim 33 wherein the
resorcin-formalin-latex comprises fluorine resin in an amount of
1-80 parts by mass per 100 parts by mass of the latex.
35. The power transmission belt according to claim 1 wherein the
cloth component is treated with a rubber paste containing graphite
in an amount of from 10-200 parts by mass per 100 parts by mass of
the rubber.
36. The power transmission belt according to claim 3 wherein the
rubber defines at least part of the teeth and is a composition
obtained by blending an unsaturated carboxylic acid metal salt and
silica with a hydrogenated nitrile rubber, blending short fibers to
produce a mixture, and crosslinking the mixture with an organic
peroxide.
37. The power transmission belt according to claim 3 wherein the
rubber defines at least a part of the teeth and is a composition
obtained by adding an unsaturated carboxylic acid metal salt to a
hydrogenated nitrile rubber in an amount of from 15-40 parts by
mass to a total polymer mass, blending silica in an amount of from
10-60 parts by mass to the total polymer mass, and blending short
fibers in an amount of from 1-20 parts by mass to the total polymer
mass.
38. The power transmission belt according to claim 36 wherein the
blended amount of silica is from 30-60 parts by mass.
39. The power transmission belt according to claim 37 wherein the
blended amount of silica is from 30-60 parts by mass.
40. The power transmission belt according to claim 36 wherein at
least one of triallylisocyanurate, triallylcyanurate,
trimethylolpropane trimethacrylate and ethylene glycol
dimethacrylate is added to the rubber as a co-crosslinking agent in
an amount of from 5 to 20 parts by mass, and an organic peroxide is
added to the rubber in an amount of from 0.2 to 10 parts by
mass.
41. The power transmission belt according to claim 37 wherein at
least one triallylisocyanurate, triallylcyanurate,
trimethylolpropane trimethacrylate and ethylene glycol
dimethacrylate is added to the rubber as a co-crosslinking agent in
an amount of from 5 to 20 parts by mass, and an organic peroxide is
added to the rubber in an amount of from 0.2 to 10 parts by
mass.
42. The power transmission belt according to claim 1 wherein the
other of the inside and outside of the body has a hardness of from
80-98 degree as measured with JIS A type hardness meter.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to power transmission belts and, more
particularly, to a power transmission belt having a cloth component
applied over a surface on which teeth are formed.
[0003] 2. Background Art
[0004] Toothed power transmission belts with a cloth component
thereon are used in a number of different environments under
conditions that are often relatively severe. For example, toothed
belts are used to drive components on automobile engines, such as a
cam shaft, an injection pump, an oil pump, a water pump, and the
like. Since automobile engine compartments are increasingly
becoming more compact, these belts are required to operate in
environments at elevated temperatures generated during engine
operation. The environmental conditions and loads encountered
dictate the need for toothed belts with higher durability.
[0005] These toothed belts are also used on rear-wheel drives of
large, high-powered motorcycles, increasingly in place of chain and
sprocket drives that have been used in the past.
[0006] These toothed belts are used also on industrial machinery
as, for example, on injection molding equipment. In this
environment, the belts may be subjected to high loads and may be
required to operate for long periods without replacement.
[0007] Toothed belts are used in other environments in which they
are commonly subjected to severe loading and environmental
conditions that tend to lead to premature failure.
[0008] To avoid premature failure, improvements have been made on
toothed belts in a number of different areas. The materials of load
carrying members that extend lengthwise of the belts have been
changed for improved durability and longevity. Thinner load
carrying members have also been developed. Further, treating agents
for load carrying cords have been devised to improve the heat
resistance thereof. These improvements have been focused on
avoiding failure due to flexing fatigue of the load carrying
members as well as inadequate heat resistance of the rubber in
which they are embedded. Additionally, hydrogenated nitrile rubber
has been used to improve heat resistance, thereby decreasing the
likelihood of premature failure.
[0009] Toothed belts used on engines in which the belts are highly
loaded, and in driving industrial machinery, are often abraded to a
significant degree at the base portion of the teeth. It is also
common for the teeth to chip as a result of abrasion at the base
portion of the teeth.
[0010] Additionally, under high loads, pulley shafts tend to bend,
whereby the travelling path defined by the pulley tends to skew.
When this occurs, the belt does not properly seat in the pulleys
and runs at an angle with respect thereto, as a result of which
there is a tendency for there to be abnormal abrasion at the belt
side surfaces that contact the cooperating pulley flanges. Cutting
and chipping of the teeth at the side surfaces may occur with this
operating condition.
[0011] In a high load application, the belts also tend to stretch
to an extent that an autotensioner does not effectively make
compensation. As a result, the belt may not be properly tensioned
whereupon operation of associated mechanisms, such as an engine or
accessories thereon, may not operate consistently or normally.
[0012] To counter abrasion of the belt side surfaces, and damaging
elongation of a belt, it is known to use a fluorine resin that
tends to reduce the coefficient of friction of the associated
surface. It is also known to apply a layered graphite, or the like,
to a cloth composition on the tooth surfaces that mesh with a
cooperating pulley. Generally, it is believed that these steps do
not account for adequate improvement, particularly with respect to
load carrying member performance.
[0013] In JP-B-58-334323, a cloth component for a toothed belt is
disclosed with separate yarns. In one of the yarns, 6-nylon or 6,
6-nylon fiber material is used for purposes of good adhesion with
rubber. In the other yarn, fluorine fibers or carbon fibers are
used. The dimensional accuracy of the toothed portion of the belt
may not be maintainable merely using fluorine fibers or carbon
fibers in the yarns. A product with this cloth component may not be
useable in the automotive environment in which a high, maintained
level of dimensional accuracy of the tooth region is required.
SUMMARY OF THE INVENTION
[0014] In one form, a power transmission belt has a body with a
length, an inside, an outside, and laterally spaced and oppositely
facing side surfaces. The body has a plurality of teeth formed on
one of the inside and outside of the body and spaced along the
length of the body. The body has a first surface at the one of the
inside and outside of the body defined at least in part by the
teeth. A cloth component has oppositely facing first and second
sides with the first side attached to the first surface and the
second side exposed to engage a pulley cooperating with the power
transmission belt. The cloth component consists of first fibers at
the first side of the cloth component with a first performance
characteristic and second fibers at the second side of the cloth
component with a second performance characteristic that is
different than the first performance characteristic. The first side
of the cloth component has different properties than the second
side of the cloth component by reason of the presence of the first
and second fibers.
[0015] In one form, the body consists of rubber that defines at
least a part of the first surface and at least one load carrying
member is embedded in the rubber and extends lengthwise of the body
adjacent the other of the inside and outside of the body.
[0016] In one form, the body consists of rubber that defines at
least a part of the first surface. The first fibers have a
composition that adheres strongly to the rubber at the first
surface. The second fibers have a composition with a low
coefficient of friction.
[0017] In one form, the first fibers have a composition that
adheres more strongly to the rubber than the composition of the
second fibers and the second fibers have a composition with a lower
coefficient of friction than the coefficient of friction of the
first fibers.
[0018] In one form, the second fibers have good abrasion resistance
characteristics.
[0019] In one form, the cloth component has a double cloth
construction.
[0020] In one form, the second fibers are fluorine fibers.
[0021] In one form, the cloth component consists of warp yarns
having nylon fibers and weft yarns having fluorine fibers, nylon
fibers, and polyurethane elastic yarns.
[0022] In one form, the cloth component has a double cloth
construction. The first fibers have a composition that adheres more
strongly to the rubber than the composition of the second fibers
and the second fibers have a composition with a lower coefficient
of friction than the coefficient of friction of the first
fibers.
[0023] In one form, the cloth component consists of warp yarns
having fluorine fibers, nylon fibers, and polyurethane elastic
yarns and weft yarns having nylon fibers.
[0024] In one form, the weft yarns consist of a plurality of first
weft yarns at the first side of the cloth component and a plurality
of second weft yarns at the second side of the cloth component and
at least the plurality of second weft yarns includes fluorine
fibers.
[0025] In one form, the warp yarns consist of a plurality of first
warp yarns at the first side of the cloth component and a plurality
of second warp yarns at the second side of the cloth component and
at least the second warp yarns include fluorine fibers.
[0026] In one form, from 20-100% of the warp yarns are woven by
being intertwined with the second weft yarns.
[0027] In one form, from 20-100% of the weft yarns are woven by
being intertwined with the second warp yarns.
[0028] In one form, the second weft yarns consist of urethane
elastic yarns that have core parts with exposed circumferences and
fluorine fibers are applied on the exposed circumferences of the
core parts.
[0029] In one form, the second warp yarns consist of urethane
elastic yarns that have core parts with exposed circumferences and
fluorine fibers are applied on the exposed circumferences of the
core parts.
[0030] In one form, the first weft yarns consist of urethane
elastic yarns that have core parts with exposed circumferences and
nylon fibers are applied on the exposed circumferences of the core
parts.
[0031] In one form, the first warp yarns consist of urethane
elastic yarns that have core parts with exposed circumferences and
nylon fibers are applied on the circumference of the core
parts.
[0032] In one form, the second side of the cloth component has an
area and the fluorine fibers in the cloth component are exposed on
the second side over from 30-100% of the area of the second
side.
[0033] In one form, the second fibers consist of fluorine fibers
having a coefficient of friction less than the coefficient of
friction of the first fibers, and the first side of the cloth
component consists of five sateen weaves with fibers that adhere
more strongly to the rubber than fibers on the second side of the
cloth component. The cloth component has warp yarns made from nylon
fibers and weft yarns made from fluorine fibers, nylon fibers, and
polyurethane elastic yarns.
[0034] In one form, the fluorine fibers consist of at least one of
a polytetrafluoroethylene, a polytrifluoroethylene, a
tetrafluoroethylene-hexafluoropropylene copolymer, a
tetrafluoroethylene-perfluoroalkoxyethylene copolymer, and a
tetrafluoroethylene-ethylene copolymer.
[0035] In one form, the fluorine fibers are polytetrafluoroethylene
fibers with a polytetrafluoroethylene content in the
polytetrafluoroethylene fibers of from 90-100 parts by mass per 100
parts by mass of the polytetrafluoroethylene fiber.
[0036] In one form, the second side of the cloth layer has an area
and the fluorine fibers in the cloth layer are exposed on the
second side over from 50-100% of the area of the second side of the
cloth layer.
[0037] In one form, a resorcin-formalin-latex treatment is applied
to the cloth component.
[0038] In one form, the resorcin-formalin-latex consists of
fluorine resin in an amount of 1-80 parts by mass per 100 parts by
mass of the latex.
[0039] In one form, the cloth component is treated with a rubber
paste containing graphite in an amount of from 10-200 parts by mass
per 100 parts by mass of the rubber.
[0040] In one form, the rubber defines at least part of the teeth
and is a composition obtained by blending an unsaturated carboxylic
acid metal salt and silica with a hydrogenated nitrile rubber,
blending short fibers therewith to produce a mixture, and
crosslinking the resulting mixture with an organic peroxide.
[0041] In one form, the rubber defines at least a part of the teeth
and is a composition obtained by adding an unsaturated carboxylic
acid metal salt to a hydrogenated nitrile rubber in an amount of
from 15-40 parts by mass to a total polymer mass, blending silica
in an amount of from 10-60 parts by mass to the total polymer mass,
and blending short fibers in an amount of from 1-20 parts by mass
to the total polymer mass.
[0042] In one form, the blended amount of silica is from 30-60
parts by mass.
[0043] In one form, at least one triallylisocyanurate,
triallylcyanurate, trimethylolpropane trimethacrylate and ethylene
glycol dimethacrylate is added to the rubber as a co-crosslinking
agent in an amount of from 5 to 20 parts by mass. An organic
peroxide is added to the rubber in an amount of from 0.2 to 10
parts by mass.
[0044] In one form, the other of the inside and outside of the body
has a hardness of from 80-98 degree as measured with a JIS A type
hardness meter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0045] FIG. 1 is a fragmentary, perspective view of one form of
power transmission belt, according to the present invention,
including a body with a cloth component;
[0046] FIG. 2 is a schematic, cross-sectional view of the cloth
component in FIG. 1 taken in a plane through the length of weft
yarns;
[0047] FIG. 3 is a few as in FIG. 2 taken from a perspective in a
plane through the length of warp yarns;
[0048] FIG. 4 is a schematic representation of a running test
apparatus for toothed belts;
[0049] FIG. 5 is a schematic representation of a section of a side
of the cloth component that engages a cooperating pulley wherein
the weave textile weave is 3/1 twilled weave;
[0050] FIG. 6 is a view as in FIG. 5 of the opposite side of the
cloth component wherein the weave textile weave is 3/1 twilled
weave;
[0051] FIG. 7 is a view as in FIG. 5 wherein the weave textile
weave is a double cloth;
[0052] FIG. 8 is a view as in FIG. 6 wherein the weave textile
weave is a double cloth;
[0053] FIG. 9 is a view as in FIG. 5 wherein the weave textile
weave is 5 sateen weave; and
[0054] FIG. 10 is a view as in FIG. 6 wherein the weave textile
weave is 5 sateen weave.
DETAILED DESCRIPTION OF THE INVENTION
[0055] A toothed belt, according to the present invention, is shown
at 10 in FIG. 1. The belt 10 has a body 12 with an endless length
extending in the direction of the double-headed arrow 14. The body
12 has an inside 16 and an outside 18. The designations "inside"
and "outside" are arbitrary as either side could be viewed as
either "inside" or "outside". The body 12 further has laterally
spaced and oppositely facing side surfaces 20, 22. The body 12 has
a plurality of teeth 24 formed on the inside of the body 12 that
are spaced at regular intervals along the length thereof. The body
has a first surface 26 at the inside thereof defined in part by the
teeth 24. The body 12 is made from rubber in which load carrying
members/cords 28 are embedded. The load carrying members/cords 28
extend lengthwise of the body 12 and define a neutral axis.
[0056] A cloth component 30 is applied to the body 12 and has
oppositely facing first and second sides 32, 34, respectively. The
first side 32 of the cloth component 30 is attached to the first
surface 26 on the body 12. The second side 34 of the cloth
component 30 is exposed to engage a cooperating pulley 36 having a
complementary configuration to that of the inside 16 of the body
12, as covered by the cloth component 30.
[0057] The cloth component 30 consists of a fabric substrate
material produced by weaving weft yarns 38, extending lengthwise of
the belt body 12, and warp yarns 40, extending laterally/widthwise
of the belt body 12.
[0058] The belt body 12 may be made from the same composition or by
combining layers having different compositions. In one form, a back
portion 42 of the body 12, outside of the load carrying
members/cords 28, consists of a blend of an unsaturated carboxylic
acid metal salt with a hydrogenated nitrile rubber. The degree of
hydrogenation of the hydrogenated nitrile rubber is at least 90% or
more, for purposes of heat resistance. More preferably, the degree
of hydrogenation is 92-98%.
[0059] The blending of the unsaturated carboxylic acid metal salt
with the hydrogenated nitrile rubber increases the tensile modulus
and hardness, potentially avoiding detrimental compression
deformation of the teeth 24. To achieve the desired tensile modulus
and elongation at failure, and further to achieve the desired
tearing strength and hardness, the unsaturated carboxylic acid
metal salt is added to the hydrogenated nitrile rubber in an amount
of 15-40 parts by mass to 100 parts by mass of the entire
polymer.
[0060] When the amount of the unsaturated carboxylic acid metal
salt is less than 15 parts by mass, the rubber hardness may not
reach the desired level. On the other hand, when the amount exceeds
40 parts by mass, the rubber may be too hard, as a result of which
the belt 10 is undesirably rigid and flexing fatigue resistance may
be inadequate. This may result in a detrimentally shortened belt
life.
[0061] The unsaturated carboxylic acid metal salt may be an
ion-bonded material of an unsaturated carboxylic acid having a
carboxylic group and a metal. The unsaturated carboxylic acid is
preferably a dicarboxylic acid such as acrylic acid or methacrylic
acid Suitable metals are berylium, magnesium, calcium, strontium,
barium, titanium, chromium, molybdenum, manganese, iron, cobalt,
nickel, copper, silver, zinc, cadmium, aluminum, tin, lead and
antimony.
[0062] Silica is blended with a mixture of the hydrogenated nitrile
rubber and unsaturated carboxylic acid metal salt The amount of
silica is preferably from 10 to 40 parts by mass per 100 parts by
mass of the entire polymer.
[0063] When the amount of silica is less than 10 parts by mass, the
desired effect from the silica may not be achieved. On the other
hand, when the amount of silica is larger than 40 parts by mass,
the Mooney viscosity of the rubber increases In that case, when the
belt is molded, the tooth shape may not be accurately produced and
molding defects may be more prevalent.
[0064] The blend further is a crosslinked product of the rubber
having from 5-20 parts by mass of tryallyl isocyanurate (TAIC) as a
co-crosslinking agent and from 0.2 to 10 parts by mass of an
organic peroxide blended therewith
[0065] By blending a specific co-crosslinking agent with a rubber
containing an unsaturated carboxylic acid metal salt, the viscosity
may not increase during uncrosslinking, facilitating processing
such as rolling or molding. After crosslinking, good hardness and
strength may be achieved.
[0066] The ratio of the hydrogenated nitrile rubber and the
unsaturated carboxylic acid metal salt is preferably from 98:2 to
55:45. If the proportion of the hydrogenated nitrile rubber is
greater than 98, abrasion resistance may be inadequate. When the
proportion is smaller than 55, while abrasion resistance may be
good, the flexing properties of the belt deteriorate It is also
possible to form a matrix rubber by blending the hydrogenated
nitrile rubber containing the unsaturated carboxylic acid metal
salt in order to adjust the ratio.
[0067] The organic peroxide is used as a crosslinking agent.
Examples thereof include di-t-butyl peroxide, dicumyl peroxide,
t-butylcumyl peroxide, 1,1-t-butyl-peroxy-3,3,5-trimethyl
cyclohexane, 2,5-dimethyl-2,5-di (t-butylperoxy)hexane-3,
bis(t-butylperoxy-diisopropyl)benzene,
2,5-dimethyl-2,5-di(benzoylproxy)hexane, t-butylperoxybenzoate and
t-butylperoxy-2-ethylhexyl carbonate.
[0068] The blending amount is preferably from 0.2 to 10 parts by
mass per 100 parts by mass of the matrix rubber.
[0069] When the blending amount is less than 0.2 parts by mass,
crosslinking may not be adequately carried out When the blending
amount exceeds 10 parts by mass, elasticity may be detrimentally
reduced.
[0070] Silica is blended in an amount from 10 to 60 parts by mass,
and more preferably from 30 to 60 parts by mass, per 100 parts by
mass of the matrix rubber.
[0071] When the amount is less than 10 parts by mass, the adhesion
forces between the rubber and load carrying members/cords 28 may be
inadequate This may lead to a condition where the load carrying
members/cords 28 peel and thus protrude.
[0072] When the amount exceeds 60 parts by mass, viscosity under
unvulcanization increases and the belt cannot be properly formed 30
parts by mass or more is preferable to achieve a high belt
hardness.
[0073] To obtain additional strength, short fibers 44 may be added
in an amount of 1-20 parts by mass per 100 parts by mass of the
entire polymer.
[0074] Suitable examples of the co-crosslinking agent include:
TAIC, TAC, 1,2-polybutadiene, metal salts of unsaturated caboxylic
acid, oximes, guanidine, trimethylolpropane, trimethacrylate,
ethylene glycol dimethacrylate and N,N'-m-phenylene bismaleimide.
Preferably, at least one of TAIC and TAC is used. By using TAIC or
TAC, the hardness of the rubber after crosslinking can be increased
as compared with rubbers using other crosslinking agents.
[0075] Further, the viscosity of an uncrosslinked rubber does not
rise significantly and, as a result, workability and moldability do
not significantly deteriorate.
[0076] The blending amount of the co-crosslinking agents is
preferably in the range of 5-20 parts by mass.
[0077] When the amount is less than 5 parts by mass, the hardness
of the belt may not be adequate When the amount exceeds 20 parts by
mass, the degree of crosslinking may be excessive, as a result of
which tear resistance force is detrimentally decreased.
[0078] In addition to the above, depending upon the particular
application for the belt, it may be desirable to blend fillers for
improving abrasion resistance, such as: carbon black, calcium
carbonate and talc, that are generally blended with a rubber; and
additives such as crosslinking assistants, crosslinking
accelerators, plasticizers, stabilizers, processing assistants,
antioxidants and coloring agents Methods of mixing those blending
agents include, but are not limited to, conventional means such as
kneading using a Banbury mixer, or a kneader.
[0079] The cloth component 30 is made so that first fibers 46, at
the first side 32 of the cloth component 30, have a first
performance characteristic and second fibers 48, at the second side
34 of the cloth component 30, have a second performance
characteristic that is different than the first performance
characteristic The nature of the first and second fibers 46, 48,
and the manner in which they are incorporated into the cloth layer,
as explained below, cause the cloth component 30 to have different
properties at the opposite sides 32, 34 thereof.
[0080] In one form, the second fibers 48 on the cloth component
side 34 that cooperates with the pulley 36 have a coefficient of
friction lower than that of the first fibers 36 on the first side
32 of the cloth component 30 that is adhered to the belt body
surface 26. The fibers 46 on the first side 32 of the cloth
component 30 are of a type that adheres more aggressively to the
belt body rubber than do the fibers 48.
[0081] More specifically, as seen in FIG. 2, the second fibers 48
preferably consist of at least fluorine fibers. These fibers 48 are
preferably exposed on the first side 32 of the cloth component 30
on over from 0-20% of the area of the first side 32
[0082] The cloth component 30 is preferably a double cloth fabric.
In one form, the warp yarns 40 include nylon fibers, with the weft
yarns 38 including fluorine fibers, nylon fibers and polyurethane
elastic yarns. The weft yarns 38 preferably include a plurality of
first weft yarns 38a exposed at the second side 34 of the cloth
component 30 and a plurality of second weft yarns 38b at the first
side 32 of the cloth component 30. At least the plurality of first
weft yarns 38a consists of a yarn with fluorine fibers.
[0083] It is preferred that from 20-100% of the warp yarns 40 be
interwoven with the plurality of first weft yarns 38a. The first
weft yarn 38a is preferably a yarn made from a urethane elastic
yarn with a core part 50 having fluorine and/or nylon fibers 48 on
the circumference thereof. The yarn having the fluorine fibers on
the circumference thereof is preferably present in an amount of
40-100% of the plurality of first weft yarns 38a.
[0084] The plurality of second weft yarns 38b preferably consists
of yarns having a core part 52 with nylon fibers 48 on the
circumference thereof. The fluorine fibers 48 in the cloth
component 30 preferably are exposed at the surface 53 of the second
side 34 of the cloth component 30 on over 30-100% of the total area
of the surface 53. In one exemplary embodiment having the
construction shown in FIG. 2, the fluorine fibers 48 are exposed
over approximately 75% of the area of the surface 53.
[0085] As seen in FIG. 3, the cloth component 30 may have weft
yarns 38 consisting of nylon fiber, with the warp yarns 40
consisting of fluorine fibers, nylon fibers, and polyurethane
elastic yarns. The warp yarns 40 consist of a plurality of first
warp yarns 40a at the surface 53 on the second side 34 of the cloth
component 30 and a plurality of second warp yarns 40b at the first
side 32 of the cloth component 30. At least the plurality of first
warp yarns 40a is made of yarns that include fluorine fibers.
[0086] It is preferred that from 40-100% of the number of weft
yarns 38 be woven by being intertwined with the first warp yarns
40a. The first warp yarns 40a are preferably yarns consisting of a
core part 54 having at least one of fluorine fibers or nylon fibers
48 on the circumference thereof. The yarns having the fluorine
fiber on the circumference thereof are preferably present in an
amount of 40-100% of the plurality of first warp yarns 40a.
[0087] The plurality of second warp yarns 40b preferably has a
urethane elastic yarn core part 56, with nylon fibers 48 on the
circumference thereof.
[0088] The fluorine fibers 48 in the cloth component 30 preferably
are exposed on the surface 53 of the second side 34 of the cloth
component 30 over from 30-100% of the total area thereof. The
proportion of fluorine fibers, as noted previously, may be exposed,
for example, over 75% of the area of the surface 53
[0089] In another embodiment, the cloth component 30 is preferably
a double cloth fabric. The second side 34 is made with fibers
having a low coefficient of friction and good abrasion resistance.
The fibers 46 are of a composition to strongly adhere to the rubber
in the body 12. The coefficient of friction at the surface 53 on
the second side 34 is preferably less than 2.
[0090] If the dynamic friction coefficient is greater than 0.2,
thrust forces become relatively large and the belt 10 may move and
remain in front of an axis. This may give rise to a problem where
the side surfaces 20, 22 become damaged, eventually resulting in
belt breakage.
[0091] The cloth component 30 may be woven by a five sateen weave
process. With this construction, the fibers 48 on the surface on
the second side 34 have a coefficient of friction less than the
fibers 46 on the first side 32 As in the prior embodiments, the
fibers 46 on the first side 32 have a composition that adheres more
positively to the rubber in the body 12 than do the fibers 48 on
the second side 34. The fibers 48 with the low friction coefficient
preferably are present on the first side 32 over 0-20% of the area
thereof.
[0092] With the five sateen weave process, it is preferable that
the warp yarns 40 include nylon fibers, with the weft yarns 38
including fluorine fibers, nylon fibers, and polyurethane elastic
yarns.
[0093] In one form, the weave textile weave of the double cloth is
made up of warp yarns consisting of 6,6-nylon fiber, and weft yarns
consisting of urethane elastic yarns and polytetrafluoroethylene
fibers. The weave textile weave is 3/1 twilled weave, or a weave
wherein the second side 34 is a 1/3 twilled weave, with the first
side 32 a 2/2 twilled weave.
[0094] The exposure of the polytetrafluoroethylene fibers and nylon
fibers at the opposite sides of the cloth component 30, resulting
with a 3/1 twilled weave process is shown in FIGS. 5 and 6 wherein
the former is identified as PF and the latter as NF. FIG. 5 depicts
the second side 34, with FIG. 6 depicting the first side 32.
[0095] In FIGS. 7 and 8, views corresponding respectively to FIGS.
5 and 6 are shown for the cloth component 30 with a weave textile
weave that is a horizontal double cloth, with the fibers similarly
identified as "NF" and "PF".
[0096] In FIGS. 9 and 10 views corresponding respectively to FIGS.
5 and 6 are shown for the cloth component 30 with a weave textile
weave that is a five sateen weave. The exposed nylon fibers are
likewise identified as "NF".
[0097] The weave textile weave of the five sateen weaves may be any
single cloth of 3/1 twilled weave or five sateen weave.
[0098] In the case of the five sateen weave, in one form, the warp
yarns are made of 6,6-nylon fiber, with the weft yarns made of
urethane elastic yarns and polytetrafluoroethylene fibers.
[0099] With the cloth component 30 in the form of a single cloth or
a double cloth, preferably the fibers exposed at the surface 53 on
the second side 34 are predominantly fluorine fibers. The fluorine
fibers may be one or a combination of polytetrafluoroethylene,
polytrifluoroethylene and tetrafluoroethylene-hexafluoropropylene
copolymer, a tetrafluoroethylene-perfluoroalkoxyethene copolymer,
and a tetrafluoroethylene-ethylene copolymer. Others fibers are
contemplated.
[0100] Particularly effective are polytetrafluoroethylene fibers.
The makeup of the polytetrafluoroethylene may be one or more of
PTFE (polytetrafluoroethylene), FEP (tetrafluoroethylene,
hexafluoropropylene copolymer), PFA (tetrafluoroethylene,
perfluoroalkoxy group copolymer), ETFE (tetrafluoroethylene, olefin
copolymer), and the like. While PTFE (polytetrafluoroethylene) is
preferred, other fibers will perform adequately. If
polytetrafluoroethylene fibers are used, preferably PTFE is present
in an amount from 90-100 parts by mass per 100 parts by mass of the
polytetrafluoroethylene fibers.
[0101] In the case of a five sateen weave cloth component 30, it is
preferred that the fluorine fibers be exposed on the surface 53 on
the second side of the cloth component 30 over from 50-100% of the
area of the surface 53.
[0102] The hardness of the outside surface 58 of the body 12 is
preferably 85 degree or more, and preferably from 80-98 degree, as
measured with a JIS A hardness meter.
[0103] With this hardness, even under heavy load, rubber
compression can be suppressed, as can heat generation resulting
from this condition. Abrasion and damage to the belt side surfaces
20, 22 can be avoided.
[0104] The load carrying members/cords 28 are preferably
cords/ropes that exhibit a low degree of elongation and high
strength. Suitable examples are twisted ropes made form organic
fibers such as aramid fibers, polyamide fibers, polyethylene
terephthalate fibers, and polyester fibers having
ethylene-2,6-naphthalate as the main structural unit Inorganic
fibers such as glass fibers may be used. Alternatively metal fibers
may be used. Each load carrying member/cord 28 is adhered to the
rubber in the body 12 after performing a resorcin-formalin-latex
treatment. A rubber paste, or the like, may be applied to the
surface following the resorcin-formalin-latex treatment.
[0105] Adhesion treatment is carried out by dipping the fibers in
resorcin-formalin-latex (RFL) liquid. The dipped fibers are heated
and dried after which an adhesive layer is uniformly applied on the
surface thereof.
[0106] Other treatments may be used. For example, pre-treatment
with an epoxy or isocyanate compound may be performed, after which
an RFL liquid is applied.
[0107] The RFL liquid is obtained by mixing an initial condensate
of resorcin and formalin with a latex. Examples of a suitable latex
are: chloroprene, stylene-butadiene-vinylpyridine terpolymer,
hydrogenated nitrile, and NBR. The hydrogenated nitrile is
preferably made from the same rubber that is in the back portion
42, or the rubber in a cushion layer 60, in which the load carrying
members/cords 28 are embedded.
[0108] The advantages of the present invention will be described
with respect to specific examples, as set forth below.
[0109] Rubbers made with the formulation shown in Table 1, below,
were kneaded by well known methods to prepare rubber sheets having
a predetermined thickness produced by calendar rolls.
TABLE-US-00001 TABLE 1 Inventive Example Comparative Example A-1
A-2 A-3 A-4 A-5 A-6 A-7 A-8 A-9 A-10 A-11 A-12 A-13 A-14 A-15 H-NBR
containing 20 20 20 20 20 60 50 40 60 60 60 -- 20 30 50 unsaturated
carboxylic acid*1) H-NBR*2) 80 80 80 80 80 40 50 60 40 40 40 100 80
70 50 Stearic acid 1 1 1 1 1 1 1 0.3 1 1 1 1 1 0.5 -- Antioxidant 2
2 2 2 2 2 2 2 2 2 2 2 2 1 1.5 Carbon black 40 40 40 40 40 -- -- --
40 40 50 40 40 40 -- Plasticizer 2 5 5 5 5 20 20 6 5 5 5 2 2 5 10
Silica 10 10 20 20 20 40 40 40 10 10 -- 10 10 -- -- Polyethylene
glycol 1 1 1 1 1 1 1 -- 1 1 -- 1 1 -- -- Peroxide*3) 2 2 2 2 2 2 2
-- 2 2 2 2 2 -- -- TAlC 5 10 10 20 -- 5 5 2 -- 10 10 5 -- -- -- TAC
-- -- -- -- 5 -- -- -- -- -- -- -- -- -- --
N,N-m-phenylenedimaleimide -- -- -- -- -- -- -- -- -- -- -- -- 5 --
--
[0110] The physical properties thereof were then measured. The
results are shown in Table 2, below. TABLE-US-00002 TABLE 2
Inventive Example Comparative Example A-1 A-2 A-3 A-4 A-5 A-6 A-7
A-8 A-9 A-10 A-11 A-12 A-13 Viscosity 48.1 44.6 57.9 45.3 48.3 61.6
60.3 57.7 49.8 40.2 44.1 39.7 65.1 (125.degree. C.) Hardness 90 93
94 95 90 93 95 95 83 85 88 80 86 M100 [MPa] 22.6 -- -- -- 22.4 16.1
14.1 12.5 12.1 12.9 17.9 20.1 13.5 TB [MPa] 23.3 21.5 21.1 20.5
23.5 27.7 25.1 26.2 15.8 15.6 24.1 26.3 23.0 EB [%] 104 96 93 88
105 251 223 257 268 253 158 290 230 Adhesion to 340 330 330 330 340
315 380 380 370 100 100 380 330 aramid core Rubber Rubber Rubber
Rubber Rubber Rubber Rubber Rubber Rubber Interface Interface
Rubber Rubber wire [N/25 mm] tearing tearing tearing tearing
tearing tearing tearing tearing tearing peeling peeling tearing
tearing
[0111] The cloth component 30 was made with the fibers shown in
Table 3, produced below. TABLE-US-00003 TABLE 3 B-1 B-2 B-3 B-4 B-5
Cloth Nylon 6,6 component warp yarn Cloth Nylon PTFE PTFE PTFE
Aramid component fiber + Fiber + fiber + fiber + fiber weft yarn
urethane urethane urethane urethane elastic elastic elastic elastic
yarn yarn yarn yarn Cloth 2/2 1/3 Double 2/2 component twilled
twilled cloth twilled weave weave weave weave textile weave
Thickness 0.350 of cloth component (mm)
[0112] Treatments were carried out as shown in Table 4, below
TABLE-US-00004 TABLE 4 C-1 C-2 C-3 Resorcin -- -- -- Formalin -- --
-- Water -- -- -- Latex -- -- -- Fluon -- -- -- Compounded rubber
F-1 100 -- 100 Compounded rubber F-2 -- 100 -- MEK 2000 1250 570
PAPI-135 100 -- -- Graphite AT-20 -- 100 --
[0113] The rubber paste treatment of Table 4 starts with the rubber
blend in Table 5, below. TABLE-US-00005 TABLE 5 F-1 F-2 H-NBR*1 100
100 Zinc flower 2 2 Stearic acid 0.5 0.5 HAF carbon black 40 --
Graphite AT-20 -- 40 Plasticizer 10 10 Vulcanization accelerator --
-- Organic peroxide 2.0 2.0 Sulfur -- --
[0114] The rubber blend of Table 5 is dissolved in methyl ethyl
ketone, as in C-2 and C-3 in Table 4. A polyarylpolyisocyanate
(trademark PAPI.TM.) as an isocyanate compound is then added to the
resulting mixture to prepare a treating liquid An antifriction
material such as MBI,
N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, fluorine resin
powder or graphite is appropriately added to the treating liquid.
The tooth cloth is dipped in the resulting treating liquid and
dried.
[0115] In Inventive Example 11, a cloth component/canvas 30 was
subjected to the treatment in Table 4. The canvas had warp yarns 40
made from nylon fibers, and weft yarns 38 made from
polytetrafluoroethylene fibers, nylon fibers, and polyurethane
elastic yarns. The weft yarns were made with a plurality of first
weft yarns at the second side 34 that engage a pulley and a
plurality of second weft yarns on the first side 32 applied to the
belt body 12. The plurality of first weft yarns contained
polytetrafluoroethylene fibers. The proportion of
polytetrafluoroethylene fibers in the plurality of first weft yarns
exposed at the surface 53 of the second side was 50% of the entire
surface area. In this Example, the proportion of the
polytetrafluoroethylene fibers exposed at the first side 32 of the
canvas was 0%.
[0116] In Inventive Example 12, a cloth component/canvas 30 was
subjected to the treatment shown in Table 4. The canvas had the
same constitution as that in Inventive Example 11. A plurality of
first weft yarns contained the polytetrafluoroethylene fibers.
These fibers were exposed over 66.7% of the area of the surface 53
at the second side 34. The proportion of the
polytetrafluoroethylene fibers exposed at the first side 32 was
0%.
[0117] In Inventive Example 13, a cloth component/canvas 30 was
subjected to the treatment shown in Table 4 and had the same
constitution as that for Inventive Example 11. The plurality of
first weft yarns exposed at the second side 34 had
polytetrafluoroethylene fibers. These fibers were exposed at the
second side 34 over 75% of the surface area. The proportion of the
polytetrafluoroethylene fibers exposed at the first side 32 was
0%.
[0118] In Inventive Example 14, a cloth component/canvas 30 was
subjected to the treatment shown in Table 4. The canvas had the
same constitution as that in Inventive Example 11. The plurality of
first weft yarns exposed at the second side 34 had
polytetrafluoroethylene fibers. The fibers were exposed at the
second side 34 over 80% of the surface area. The proportion of
polytetrafluoroethylene fibers exposed at the first side 32 was
0%.
[0119] With Comparative Example 11, a canvas was subjected to the
treatment shown in Table 4, The canvas had warp yarns consisting of
nylon fibers and weft yarns consisting of nylon fibers and
polyurethane elastic yarns. No polytetrafluoroethylene fibers were
used. The dynamic friction coefficient at the second side of the
canvas was measured. The dynamic friction coefficient measurement
method was carried out with a face pressure of 0.185 g/mm and a
line speed of 500 mm/min. The test results are shown in Table 6.
TABLE-US-00006 TABLE 6 Inven- Inven- Inven- Inven- tive tive
Compar- tive tive Exam- Exam- ative Example Example ple ple Exam-
11 12 13 14 ple 11 Proportion of 50 66.7 75 80 0 fluorine fiber
appearing on tooth portion surface (%) (In surface area of tooth
portion) Proportion of 0 0 0 0 0 fluorine fiber appearing at rubber
side (%) (in surface area of tooth portion) Adhesive 135 135 135
135 135 force Ab (N/25 mm) Dynamic 0.20 0.21 0.18 0.18 0.24
friction coefficient
[0120] As seen from Table 6, the dynamic friction coefficient of
the Inventive Examples ranged from 0.18 to 0.21, compared to 0.24
for Comparative Example 11. The dynamic friction coefficient is
adequately small even with the proportion of
polytetrafluoroethylene on the second side as low as 50%.
[0121] The various cloth components were wound around a mold to
begin preparation of a belt. The mold had 120 teeth of ZBS tooth
form. A load carrying cord/member, as shown in Table 7, below, was
used, having been subjected to adhesion treatment with a rubber
paste obtained by dissolving RFL in a hydrogenated rubber in a
solvent such as toluene. TABLE-US-00007 TABLE 7 No. D-1
Constitution K-Glass 3/19 Strength (N/number) 1400 Elongation (%)
4.0
[0122] A pair of SZ twist components was wound spirally with a
predetermined tension at a pitch shown in Table 8, below.
TABLE-US-00008 TABLE 8 No. E-1 Pitch (mm/number) 1.4
[0123] The rubber sheet of Table 1 was adhered to the load carrying
cords/members to produce a preform that was introduced into a
vulcanization receptacle, wherein teeth were formed using a
conventional pressure forming system. Pressure vulcanization was
carried out at 165.degree. C. for 30 minutes. Each belt back
surface was polished to a constant thickness, with the belt cut to
a width of 30 mm. Adhesion between the cloth component and rubber
in the teeth was performed as shown in Table 9, below.
TABLE-US-00009 TABLE 9 Compar- Compar- Compar- Inventive Inventive
ative ative ative Item Example 8 Example 9 Example 6 Example 7
Example 8 Rubber A-8 Canvas B-3 B-4 B-1 B-2 Treatment C-1 + C-2 C-1
+ C-3 C-1 + C-2 Adhesive 270 275 300 40 35 force Ab (M/25 mm)
Dynamic 0.15 0.15 1.5 1.0 0.6 friction coefficient
[0124] The belts had a 30 mm width, with 120 teeth of ZBS form and
a pitch of 9.525 mm. This configuration is normally identified as
120 ZBS30.
[0125] The testing apparatus for the belts, as shown at 70 in FIG.
4, was used. The apparatus 70 consists of a crank/drive pulley 72
(with 22 teeth), a cam pulley 74 (with 44 teeth), a water pump
pulley 76 (with 19 teeth), an eccentric pulley 78, and an idler 80,
each rotatable around spaced, parallel axes 82, 84, 86, 88, 90,
consecutively. The eccentric pulley 78 was part of an autotensioner
92.
[0126] A tension of 3700 N was applied to the belts B with the
crank/drive pulley 72 operated at 4,000 rpm The initial tension was
350N.
[0127] Thrust force and degree of damage on the edge faces were
evaluated. The evaluation was conducted as follows. In the toothed
portions at both edges of the belt B, the front surface of the
toothed portions was marked out with a white ink. The test was
conducted with the crank/drive pulley 72 rotated at 4,000 rpm for
200 hours. The residual thickness of the cloth component after
running was evaluated. The relationship between the abrasion
phenomenon and the residual thickness of the cloth component are
shown in Table 10. TABLE-US-00010 TABLE 10 Grade Residual mark Edge
face phenomenon 1 100% No damage 2 60% Damage: middle to small 3
30% Damage: large to middle 4 None Large damage
[0128] The results of the running test are shown in Table 11 below.
TABLE-US-00011 TABLE 11 Inventive Example Comparative Example 1 2 3
4 5 6 7 8 1 2 3 4 5 Rubber A-1 A-2 A-3 A-4 A-5 A-6 A-7 A-8 A-9 A-10
A-11 A-12 A-13 Canvas B-3 B-4 B-3 B-1 Treatment C-1 + C-2 Degree of
1 1 1 1 1 1 1 1 2 2 2 4 -- damage of edge face*1) Thrust force 5 4
3 3 5 3 3 3 12 11 10 25 -- (N)
[0129] As seen in Table 9, with Inventive Examples 8 and 9, the
dynamic friction coefficient was decreased while maintaining good
adhesion As seen in Table 10, Inventive Examples 8 and 9 had a
small dynamic friction coefficient that effectively maintained the
thickness of the cloth component As seen in Comparative Examples 7
and 8, the dynamic friction coefficient was relatively small, but
due to relatively weak adhesion forces, breakage occurred at a
relatively early stage.
[0130] As seen in Tables 2 and 11, because with Comparative Example
1 the amount of TAIC was as small as 2 parts by mass, insufficient
hardness was obtained. As a result, slippage of the back face was
reduced, with thrust forces increased.
[0131] With Comparative Examples 2 and 3, because silica was not
added, good adhesion with the load carrying members/cords was not
obtained. Interface peeling occurred.
[0132] With Comparative Example 4, because unsaturated carboxylic
acid was not used, and H-NBR was used alone, the hardness did not
increase and slippage was relatively low As a result, the degree of
damage at the edge faces increased.
[0133] Comparative Example 5 uses N,N'-m-phenylenebismaleimide as
the co-crosslinking agent. Because the viscosity of the rubber was
too high in the uncrosslinked state, the tooth shape could not be
accurately formed.
[0134] With Inventive Examples 1-5, by reason of the interaction
due to the increased amount of TAIC or TAC and silica, hardness was
increased, and the adherence to the load carrying member/cord was
good. Peeling did not occur.
[0135] With Inventive Example 6, although within the range of the
Inventive Examples, it is understood that where the amount of H-NBR
containing the unsaturated carboxylic acid metal salt was too
large, adhesion forces decreased, although the rubber had a high
hardness.
[0136] Belts having the same size as Inventive Examples 1-8 were
prepared using the rubber sheet, canvas, and treating liquid of the
canvas shown in Table 12. They were made in the same way as
Inventive Example 10, Comparative Example 9, and Comparative
Example 10.
[0137] These belts were subjected to a biaxial high load test. The
test conditions were as follows. The driving pulley had 33 teeth,
with the driven pulley having 61 teeth. The driving pulley was
driven at 1200 rpm with a load of 490 Nm with an initial belt
tension of 550 N.
[0138] Inventive Example 10 had a life of 465 hours Comparative
Examples 10 and 11 had lives of only 157 and 274 hours, which were
shorter than that for Inventive Example 10.
[0139] Generally, the inventive belt 10 is particularly adaptable
for high load applications. The belt 10 may be constructed to have
good abrasion resistance and resistance to chipping. Tooth damage
due to abrasion can be reduced by reason of decreasing the
frictional coefficient of the cloth component 30. Dimensional
accuracy of the belt shape can be achieved at manufacture and
maintained, whereby consistent operation of associated equipment,
such as an engine or power transmission system, can be
achieved.
[0140] At the same time, good adhesion between the cloth component
30 and rubber in the body 12 may be established so that separation
of the cloth component from the body 12 is avoided.
[0141] The formation of the cloth component may be such that the
low coefficient fibers are not presented in an appreciable amount
at the first side, as might lower adhesion between the cloth
component 30 and body.
[0142] With the above advantages, long belt life may be
anticipated.
[0143] The foregoing disclosure of specific embodiments is intended
to be illustrative of the broad concepts comprehended by the
invention.
* * * * *